The Effect of a Comfort Scale Compared with a Pain Numerical Rating Scale on Opioid Consumption in the Post-Anaesthesia Care Unit: The COMFORT Study

Academic Background

Postoperative pain management is a critical topic in anaesthesiology and intensive care medicine. Effective pain assessment tools can help physicians optimize postoperative analgesia, reduce opioid consumption, and thereby lower the risk of drug-related side effects. Currently, the most commonly used tools for postoperative pain assessment are the Numerical Rating Scale (NRS) and the Visual Analogue Scale (VAS). However, these scales primarily focus on pain intensity and overlook the emotional experience and overall comfort of patients. Recent studies have shown that the use of negative words (e.g., “pain”) may increase patients’ perception of pain and anxiety, while positive communication may improve patient comfort. Based on this, researchers have proposed using a Comfort Scale as an alternative to traditional pain assessment tools to reduce postoperative opioid consumption.

Source of the Paper

This paper was co-authored by Nicolas Fusco, Ludovic Meuret, and other scholars from multiple hospitals and research institutions in France, published in the British Journal of Anaesthesia (online publication on September 7, 2024). The study was supported by the French Society of Anaesthesia and Intensive Care (SFAR) and conducted as a multicenter randomized controlled trial across 29 centers.

Study Design and Methods

Study Design

This was a prospective, multicenter, parallel-group, cluster-randomized controlled trial aimed at comparing the effects of using a Comfort Scale versus the NRS on postoperative opioid consumption. The study enrolled 885 patients, with data from 860 patients included in the final analysis. The primary endpoint was opioid consumption in the Post-Anaesthesia Care Unit (PACU) (measured in morphine equivalents), while secondary endpoints included postoperative pain, nausea and vomiting, PACU length of stay, and patient satisfaction.

Study Population

The study population consisted of French-speaking patients aged 18 and above who were scheduled to undergo surgery requiring postoperative opioid therapy. Exclusion criteria included inability to understand the assessment scales, long-term preoperative opioid use, opioid addiction, pregnancy, breastfeeding, and legally protected adults.

Randomization and Interventions

The 29 centers were randomized into two groups: the Comfort Scale group and the NRS group. In the Comfort Scale group, postoperative pain was assessed using the Comfort Scale, while in the NRS group, the traditional NRS was used. All patients received standard postoperative care, including intravenous morphine titration and prevention of postoperative nausea and vomiting (PONV).

Data Collection and Analysis

The primary endpoint was opioid consumption in the PACU, while secondary endpoints included the number of postoperative pain episodes, PONV episodes, time to reach an Aldrete score ≥9, and patient satisfaction. Data analysis employed mixed models and logistic regression models, accounting for the effects of cluster randomization.

Results

Primary Outcome

The study found no significant difference in opioid consumption in the PACU between the Comfort Scale group and the NRS group (median [interquartile range]: 0 [0-5] mg vs. 0 [0-6] mg; p=0.2436). The majority of patients in both groups (59% in the Comfort Scale group and 56% in the NRS group) did not require any opioids in the PACU.

Secondary Outcomes

For secondary endpoints, there were no significant differences between the two groups in terms of postoperative pain, PONV episodes, time to reach an Aldrete score ≥9, or patient satisfaction. Regardless of the type of surgery, opioid consumption did not differ significantly between the two groups.

Discussion and Conclusion

Discussion

Although the study hypothesized that using a Comfort Scale would reduce postoperative opioid consumption, the results did not support this hypothesis. This may be related to the generally low opioid consumption observed in the study, making it difficult to detect significant differences between the groups. Additionally, the study found that postoperative pain intensity and PONV episodes were low, which may reflect recent improvements in postoperative pain management.

Conclusion

This study demonstrated that using a Comfort Scale to assess postoperative pain did not significantly reduce opioid consumption. However, the results also indicated that postoperative pain and opioid consumption were low in both groups, which may reflect advancements in current clinical practice. Future research should focus on patient populations at higher risk for postoperative pain and opioid consumption.

Highlights of the Study

1. Novel Hypothesis: This study is the first to explore the impact of using a Comfort Scale as an alternative to traditional pain assessment tools on postoperative opioid consumption.
2. Multicenter Randomized Controlled Design: The study employed a rigorous multicenter randomized controlled design, ensuring the reliability and generalizability of the results.
3. Improvements in Postoperative Pain Management: The results showed that postoperative pain and opioid consumption were generally low, reflecting recent advancements in postoperative pain management.

Significance and Value of the Study

This study provides a new perspective on postoperative pain management. Although the Comfort Scale did not significantly reduce opioid consumption, it highlights the importance of positive communication in postoperative care. Future research should further explore how to better apply positive communication techniques in postoperative care to reduce patients’ perception of pain and opioid use.